Im on metformin,victoza,glipizide but been having stomach extended and fullness left side pain which one should i stop? or replace with what?

Diabetes Mellitus DM: Both metformin and victoza (liraglutide) can cause the stomach issues. However at your age diabetes is preventable and reversible. Focus on changing your lifestyle and so you can get off all the medications. Glipizide does not cause those symptoms but can make the insulin burn out faster. So the solution is to talk to your doc about weaning off the last medication added working on lifestyle and reversing DM.